How somatic and zygotic embryos develop in Pinus species is still poorly understood. However, the studies reported in this thesis are an important base for further research in embryology of Pinus. The transcriptome study provides an enormous source of data which can be used for further investigations of the molecular regulation of early embryo development. Especially interesting are the novel transcripts, i.e. transcripts with no homologue in Arabidopsis or other angiosperm species, which might be unique to species belonging to Pinus (or conifers). Functional studies of these genes would greatly expand our understanding of the regulation of embryo development in Pinus species.
Functional studies of the candidate genes, identified in paper (IV), are at present conducted in embryogenic cultures of Norway spruce. In the next step it will be important to perform functional studies in Scots pine. This requires that an efficient protocol for transforming embryogenic cultures of Scots pine is developed. None of the standard protocols used for transformation of conifers has so far been applicable to Scots pine.
Since there is a high risk of establishing cell lines giving rise to abnormal cotyledonary embryos when the embryogenic cultures are initiated from zygotic embryos at the stage of cleavage polyembryony, it would probably be better to initiate embryogenic cultures from more differentiated tissues. To accomplish this, further research is needed for elucidating how to regain embryogenic potential in older tissues.
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Acknowledgements
I have met and worked with many fantastic people from all around the world during my years at the Plant Biology department. You have all together created such a nice working environment and directly or indirectly made it possible for me to write my thesis.
I would specially like to thank the following people:
First, I would like to thank my excellent and always optimistic supervisor Sara for giving me the opportunity to work together with her and with an interesting, however, challenging project. You are a fantastic woman and have been a true role model for me.
Secondly, I would like to thank my co-supervisors Eva, Jens, and Emma for taking the time to read and provide valuable comments on my manuscripts and thesis.
I would also like to thank all past and present members of the forest group:
Andreas, for all your help and support during the start of my PhD, for the movie nights, and for you just being a great fun guy. Daniel V, for being such a nice roommate and friend. It was great to start the PhD at the same time as you.
Emma, for becoming a supportive supervisor in the end of my PhD, but most of all for being such a nice and wonderful friend. You are always so smart and helpful! Daniel U, for letting me take part of your projects, for all the “endless”
interesting conversations and for baking delicious cookies!
Silvia and Irene, for struggling with the Pinus project together with me. I do not think I would have made it without the two of you. Silvia, I really miss you and I hope that we can meet again soon. Irene, it is great fun to work with you and you are always very helpful. Panos, for all the help with optimizing a